package com.zp.reggie.filter;

import com.alibaba.fastjson.JSON;
import com.zp.reggie.common.BaseContext;
import com.zp.reggie.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/*
检查用户是否已经完成登录
 */
@WebFilter(filterName = "loginCheckFilter", urlPatterns = "/*")
@Slf4j
public class LoginCheckFilter implements Filter {
    //路径匹配器，支持通配符的路径写法
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse respose = (HttpServletResponse) servletResponse;
        // A. 获取本次请求的URI
        String requestURI = request.getRequestURI();

        //定义不需要处理的请求路径
        String[] urls = new String[]{
                "/employee/login",
                "/employee/logout",
                "/backend/**",
                "/front/**",
                "/common/**"
        };
        //  B. 判断本次请求, 是否需要登录, 才可以访问

        boolean check = check(urls, requestURI);
        // C. 如果不需要，则直接放行

        if (check) {
            filterChain.doFilter(request, respose);
            return;
        }
        // D. 判断登录状态，如果已登录，则直接放行
        if (request.getSession().getAttribute("employee") != null) {
            log.info("用户已登录，用户id为：{}", request.getSession().getAttribute("employee"));

            /*
            在doFilter方法中, 判定用户是否登录, 如果用户登录, 在放行之前, 获取HttpSession中的登录用户信息,
            调用BaseContext的setCurrentId方法将当前登录用户ID存入ThreadLocal。
             */
            //获取当前登录用户id
            Long empId = (Long) request.getSession().getAttribute("employee");

            BaseContext.setCurrentId(empId);
            filterChain.doFilter(request, respose);
            return;
        }


        //E. 如果未登录, 则返回未登录结果,通过输出流方式向客户端页面响应数据
        respose.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));


    }

    /*
    路径匹配，判断本次是否放行
     */
    public boolean check(String[] urls, String requestURI) {
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url, requestURI);
            if (match) {
                return true;
            }
        }
        return false;
    }
}
